Wizard to Fallen-wizard Conversion

[Konrad Klar]

You (as a Wizard player) may include stage resource cards, minion resources, minion characters, and up to two Fallen-wizard character cards in your sideboard.
[...]

Seems like Wizard player is not limited as limited is FW player in question which stage resource cards, minion resources, minion characters he may include in his sideboard.
What prevents him from including Lidless Eye or The Balrog (ally)?

[Bandobras Took]

Nothing. Nor does there really need to be.

Laying aside that this is an optional rule, the massive hurdle to becoming a Fallen Wizard is that the corruption check must be equal to the corruption total or miss by one.

If the corruption check succeeds, you don't become a FW. If the corruption check fails spectacularly, you don't become a FW and lose 5 points, to boot.

Each card you devote in your sideboard to potentially becoming a FW is a card that you aren't devoting to actually winning the game as a Wizard.

So assuming the corruption check goes your way in time to make a difference in the game, you would still have to actually bring the resource in, be able to play it, *and* also play the stage card that makes the MPs actually worth something.

The Balrog ally was judged to be a bit too strong in a straight up FW deck. It is not necessarily as strong in a deck relying on the Wizard to FW Conversion rule. Even if Lidless Eye were legally playable by a FW, which is in and of itself debatable, depending on how one reads "Not a Ringwraith," the barrier to actually being able to play it in a two-deck game is already large enough to dampen its impact.

[Konrad Klar]

Nothing. Nor does there really need to be.

As I understand: it (ability to include and use later of some cards in sideboard that are not allowed for player starting as FW) may be treated as some reward for risky and hard to achieve conversion.